Replacing your track lighting with 20W LED lights will help save electricity and carbon emissions.
Low voltage track lighting typically uses very hot halogen bulbs. LED's haven't gotten to the point where they can replace all of these (up to 75W) but there are some available now that do a decent job of replacing 20W halogen bulbs while only using 3 watts. They're not as bright, but if you're just looking for an accent light or wall-washing they do the job.
LED's last 25x longer than these bulbs and run much cooler. At 8 hours usage per day, the savings can really add up in both bulb replacement and electricity.
Here's a guide for buying LED Light Bulbs: http://www.eternaleds.com/The_Definitive_LED_Light_Bulb_Buying_Guide_a/220.htm
reference link:
http://www.eternaleds.com/LED_MR16_Bulbs_s/43.htm